1. Field of the Invention
This invention relates generally to child safety seats for use in an automotive vehicle and more particularly to properly securing a child""s safety seat to a passenger seat of the vehicle.
2. Related Art
Today""s passenger vehicles have a seat restraint device, commonly known as a xe2x80x9cseat belt,xe2x80x9d for each occupant the vehicle is designed to carry. However, use of a conventional seat restraint by a small child can result in serious injury to the child in the event of a collision or other accident. To mitigate this problem, child safety seats and other devices have been developed which improve the safety afforded the child passenger. Such safety seats are typically secured to the vehicle""s passenger seats directly by the vehicle""s seat belts.
Typically the driver and passengers sitting at the sides of the vehicle are provided with a restraint apparatus comprised of an integrated shoulder harness and a lap belt, sometimes termed a xe2x80x9c3-point restraint system.xe2x80x9d Occupants sitting in a center position often have only a lap belt. For the integrated shoulder harness/lap belt device of the 3-point system, the shoulder portion is normally attached to an inertial locking wind-up reel located in the vehicle""s door pillar. The lap portion is attached to a fixed anchor near the floor of the vehicle adjacent to the door. The shoulder and lap portions are connected together as a continuous length upon which slides the male seat belt buckle. The vehicle""s mating female buckle is typically attached to a short, upright supported belt section, also securely anchored to the floor of the vehicle but near the center of the vehicle.
When the vehicle stops abruptly, the inertial reel locks up to restrain the occupant, however a few inches of belt are released prior to final lock up of the reel. This small amount of belt release is acceptable, in fact desirable, for an adult to minimize his or her injuries. However, this same small belt release is unacceptable when the belt is being used to secure a child safety seat.
To maximize the child""s safety, it is recommended that the child, in an appropriately sized child safety seat, always be placed in the center position of the rear seat of the vehicle. In this position the child""s seat is secured with the lap belt and use of the 3-point restraint system is avoided. In this central position, the child""s safety seat is secured to the vehicle by threading one end (typically the longer, male end) of the vehicle""s seat belt through the appropriate slots in the safety seat and connecting this male end with the mating female end. Typically the loose, male end of the lap belt is pulled to tighten it.
According to the Governor""s Traffic Safety Committee of the New York State Department of Transportation: xe2x80x9cThe child safety seat should be attached as tightly as possible with the vehicle""s safety belt. The seat should not move more than 1 inch toward the front of the car or side to side.xe2x80x9d In the recommended rear, center seat position, it is very difficult for an adult to bend over and lean inward to grasp the loose end of the lap belt and then generate sufficient pulling force to satisfactorily urge the child""s seat firmly down and rearward against the vehicle""s seat back. Because of this difficult access by an adult to the rear, center seat position, only rarely is a child""s safety seat properly and safely installed.
A few inventors have addressed these problems. For example Smith (U.S. Pat. No. 5,579,561), issued Dec. 3, 1996, provides a seat belt gripping device for a 3-point restraint system that clamps and locks the shoulder portion and lap portion of a seat belt together to secure the child safety seat in place on the car seat. The device is tamper resistant so that children and infant seat occupants will not be able to remove the devices while they are in use. This device is designed to eliminate the need to remove slack from the shoulder portion of the seat belt to ensure that the child safety seat does not move in a forward direction during a sudden stop or collision. This device and others like it only addresses the removal of slack from shoulder harness type belts. It does not facilitate tightening the lap-type seat belt to achieve the recommend degree of firmness in securing the safety seat.
Barley, et al. (U.S. Pat. No. 5,611,596), issued Mar. 18, 1997, specifically addresses the issue of inadequately tightened seat belts when used to secure child safety seats. Barley discloses a child safety seat with an integral seat belt tightening mechanism. Barley""s seat comprises a seat body having a seat portion and a backrest portion. Guides on the seat body define a strap path for a strap of an adult seat belt to be used to secure the child seat body to a vehicle seat. A strap deflecting lever is movable between a first position clear of the strap path and a second position in which the strap is deflected and thus tightened. Although this design increases the degree of seat belt tightness, it has only two tension positions, a minimum and a maximum. It does not permit a continuous adjustment of the tension to assure that the recommended standards are developed. In addition, Barley""s child seat is complex and would be expensive to manufacture when one considers its internal seat belt (strap) tightening mechanism. This mechanism also adds to the weight of the safety seat which makes its transportation and installation difficult.
Koledin (U.S. Pat. No. 5,839,789), issued Nov. 24, 1998, discloses a seat belt tensioning device and a system for tightly positioning a child safety seat within the confines of a vehicle comprising a belt receiving member and a tensioning means for engaging the belt receiving member and tensioning the seat belt. Koledin shows some similarity to my invention, however, he introduces substantial reliability and cost questions by his incorporation of spring biased pinch clamps, pinch clamp release levers, fixed clamp stops, a split cylinder wind-up reel, cable guides, a tensioning knob, a worm drive, a worm gear and a torsion rod. In an alternative embodiment he introduces, but does not illustrate, a screw drive and cantilever arm in lieu of the split cylinder. The arm would pull the seat belt upward to increase its tension. Koledin also suggests operating his tensioning knobs and pinch clamps with an electric motor.
Bello, et al. (U.S. Pat. No. 6,024,408), issued Feb. 15, 2002, takes a direct approach to assuring the proper installation of a child safety seat. Bello provides an auxiliary web belt that is wound around a drum of a winch. The winch is mounted on a pressure bar which is placed on a child safety seat after the seat is in position on the passenger seat, but before the child is placed in the seat. Fasteners at the ends of the auxiliary belt are attached to a vehicle seat belt that is not to be used for the child""s seat. Alternatively, the fasteners may be directly attached to the vehicle""s seat belt anchoring points. After this belt is properly anchored to the vehicle, the winch is actuated to tighten the belt thus pressing the child""s seat into the passenger seat. After the child""s seat is properly pressed against the passenger seat, the vehicle""s unused passenger seat belt is passed through the openings provided in the child""s seat and tightened to finally secure the child seat to the passenger seat of the vehicle. The winch is then released and the auxiliary belt, winch and pressure bar are removed. The child may then be placed in the properly secured safety seat. Bello""s device would appear to be effective, but at the expense of having to attach and later remove a fairly complex, multi-component secondary device i.e. the auxiliary belt, the winch, and pressure bar in a moderately complex process.
Therefore, it is a primary object of the extant invention to provide a device that eliminates the complexities and other shortcomings of the prior art while still assuring that child safety seats are properly positioned and tightened. It is a further object of this invention to provide a child""s automotive safety seat with an integral seat belt tensioning capability that is easy and simple to use. It is an additional object of this invention to provide such a safety seat that is also robust and inexpensive to produce.
This invention provides a child safety seat with an integral seat belt tensioner for properly securing the child safety seat to the passenger seat of an automotive vehicle. The invented seat belt tensioner is adapted to pull or push the belt, after the belt is buckled, to take up any slack that is in the belt. This pulling or pushing may comprise moving the belt upward and/or forward away from the seat, or may even comprise moving the belt sideways or downward. Preferably, the moving parts for pushing or pulling the belt, and the portion of the belt being pushed or pulled, is contained within the child safety seat, so that the tensioner is integrally provided in the safety seat and also out of reach of the child.
This preferred embodiment comprises a seat frame with a mechanism contained therein for receiving the seat belt and for pulling it upwards generally vertically at the rear of the safety seat. The safety seat frame has left and right sides and a central rear interior space holding the tensioner. The preferred tensioner comprises a belt holder, preferably a tube or bracket, through which the seat belt is placed so that the belt passes from side to side across the back of the safety seat. The tensioner is adapted to raise and lower the belt holder, and therefore the belt, in response to actuation of a motor, a manual crank or other handle, or other actuation system.
In one embodiment, each side of the seat frame includes a nominally vertically-disposed elongated slot and the belt holder comprises a generally horizontal hollow tube or other member that is moveable upward and downward in the elongated slots. The seat belt is conventionally attached to the vehicle, and one or more of the portions of the buckled seat belt pass through the tube. A mechanism is provided for slideably adjusting the movable tube within the slots. Adjusting the tube upwards, tightens the child""s seat against the seat of the vehicle. Adjusting the tube downwards, releases the tension allowing the seat belt to be removed from the tube and the seat to be removed from the vehicle.
The means for slidably adjusting the tube containing the vehicle""s seat belt may be various manual or automated systems, but preferably includes a reversible motor and a gear assembly. The preferred gear assembly, operated by the electric motor in the preferred embodiment, comprises a speed reducing pinion gear/ring gear pair, a drive screw rotated by the ring gear, and a drive screw follower that rides up or down the length of the drive screw depending on the rotational direction of the motor. The drive screw follower is fixedly secured to the horizontally disposed belt receiving tube. Thus, as the electric motor is operated in one direction, the seat belt is pulled upward and thus tensioned, thereby safely securing the child""s seat to the vehicle""s seat. When the direction of the motor is reversed, the tension is released.
These and many other features and attendant advantages of the invention will become apparent as the invention becomes better understood by reference to the following detailed descriptions and accompanying drawings.